Caravan builder Fleetwood Corporation has suffered an 81 per cent net profit fall as mining giants in Western Australia finish major projects.

The company's net profit in the six months to December 31 was $5.12 million, down from $26.89 million during the same period in 2011.

Chairman Michael Hardy said accommodation demand in Western Australia's Karratha region had declined at the start of the year as mining companies Rio Tinto and Woodside finished major projects.

"Occupancy at Searipple was reduced to 40 to 50 per cent of village capacity, and was lower leading up to and during the Christmas break period," he said in a statement.

The company did not provide a full-year earnings guidance, but said the outlook would improve in 2013 as the Osprey and Searipple upgrade projects in Western Australia, and the Gladstone project in Queensland, underpinned manufacturing activity.

"Fleetwood expects an improved result in the second half of the financial year," Mr Hardy said.

Lower commodity prices were blamed for falling manufacturing activity in Western Australia.

Flagging consumer sentiment was expected to affect revenue for the recreational vehicles division.

Fleetwood declared an interim dividend of 30 cents per share, down from 33 cents a year earlier.

It shares were 17 cents, or 1.71 per cent weaker, at $9.80 at 1233 AEDT.